About

Last updated 1 September 2026

Core5 is built by one person, in Spain, and used every day by the person who builds it.

Why it exists

Most work tools solve one part of a day and then ask you to keep the rest in your head. You end up with a calendar that does not know about your tasks, an inbox that does not know about your projects, and a to-do list that has never heard of either. The switching is not the annoying part — the annoying part is that nothing you learn in one place is any use in the next.

Core5 is the opposite bet: five modules that share one space, one set of keys and one idea of what your work is. Drag an email onto Tuesday at ten and it becomes a meeting that still knows which email it came from. Finish a task and the project it belongs to moves too.

Why five

Because every candidate for a sixth turned out to be part of one of the five. A timer is part of focusing. Today is part of focusing. Notes belong to the thing they are about. The number is not a slogan — it is a decision that gets defended every time something new is proposed.

How it is built

Native Swift across Apple platforms, with a Postgres database in the EU and a handful of small server functions. No Electron. No analytics. No growth team. The valuable logic lives on the server where it belongs, and the app is fast because it reads from disk first and asks the network second.

Who

Pedro Gainza. contact@core5app.com.